UINavigationBar titleView比栏本身高

Question

所以我试图在UINavigationBar上做一个类似于流行的UITabBar自定义的中心按钮。但它有一个小问题。

基本上一切都运行良好，我已调整大小，显示titleView，使用AutoLayout（topLayoutGuide）。甚至推动画也运作良好。但是流行动画失败了。它是截图或限制边界，我无法找到一个好的工作，这不会让我只想制作一个自定义控件并跳过UINavigationBar。

下面是一段视频，展示了最新动态。 http://tinypic.com/r/2vl8yl1/8

下面是自定义navigationBar的一些代码：

private let NavigationBarOffset: CGFloat = 10.0

class ActionNavigationBar: UINavigationBar {

    override init(frame: CGRect) {
        super.init(frame: frame)

        self.clipsToBounds = false
        self.contentMode = .Redraw

        // Slide the original navigationBar up to make room for the actionbutton
        transform = CGAffineTransformMakeTranslation(0.0, -NavigationBarOffset)
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func sizeThatFits(size: CGSize) -> CGSize {
        var expectedSize = super.sizeThatFits(size)

        // Adjust the height of the navigation bar
        expectedSize.height += NavigationBarOffset

        return expectedSize
    }
}

以下是获取按钮的代码：

navigationItem.title = "Browse"
navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Bookmarks, target: nil, action: nil)
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Search, target: self, action: "next")

let button = UIButton()
button.setTranslatesAutoresizingMaskIntoConstraints(false)
button.setTitle("+", forState: .Normal)
button.setTitle("", forState: .Highlighted)
button.titleLabel?.font = UIFont.boldSystemFontOfSize(40.0)
button.backgroundColor = self.view.tintColor
button.layer.cornerRadius = 27.0

let buttonWrapper = UIView(frame: CGRect(x: 0, y: 0, width: 60.0, height: 60.0));
buttonWrapper.addSubview(button)

NSLayoutConstraint(item: button, attribute: .CenterX, relatedBy: .Equal, toItem: buttonWrapper, attribute: .CenterX, multiplier: 1.0, constant: 0.0).active = true
NSLayoutConstraint(item: button, attribute: .Bottom, relatedBy: .Equal, toItem: buttonWrapper, attribute: .Bottom, multiplier: 1.0, constant: 0.0).active = true
NSLayoutConstraint(item: button, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant: 54.0).active = true
NSLayoutConstraint(item: button, attribute: .Width, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant: 54.0).active = true

navigationItem.titleView = buttonWrapper;

Answer 1

我试过override func viewDidLoad()。没有使用自定义导航栏，它对我来说很好。

override func viewDidLoad()
{
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    //self.edgesForExtendedLayout = UIRectEdge.None
    //navigationItem.title = "Browse"

    navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Bookmarks, target: nil, action: nil)
    navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Search, target: self, action: "next")



    let button = UIButton()
    //button.setTranslatesAutoresizingMaskIntoConstraints(false)
    button.frame = CGRectMake(0, 0, 40, 40)
    button.setTitle("+", forState: .Normal)
    button.setTitle("", forState: .Highlighted)
    button.titleLabel?.font = UIFont.boldSystemFontOfSize(40.0)
    button.backgroundColor = self.view.tintColor
    button.layer.cornerRadius = 20

    let buttonWrapper = UIView(frame: CGRect( 0, y: 0, width: 40, height: 40));
    //buttonWrapper.backgroundColor = UIColor.redColor()
    buttonWrapper.addSubview(button)

    /*NSLayoutConstraint(item: button, attribute: .CenterX, relatedBy: .Equal, toItem: buttonWrapper, attribute: .CenterX, multiplier: 1.0, constant: 0.0).active = true
    NSLayoutConstraint(item: button, attribute: .Bottom, relatedBy: .Equal, toItem: buttonWrapper, attribute: .Bottom, multiplier: 1.0, constant: 0.0).active = true
    NSLayoutConstraint(item: button, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant: 54.0).active = true
    NSLayoutConstraint(item: button, attribute: .Width, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant: 54.0).active = true*/

    navigationItem.titleView = buttonWrapper;
}

Answer 2

一般来说， UINavigationBar hight为65.在标题为 StatusBar 之前需要大约10 yOffset。所以你可以将你的标题设置在NavigationBar的10到65 yOffset之内。按钮的最大高度为（65-10）= 55。

所以你有两个解决方案：

1. 您可以更改按钮的高度和宽度，

   let buttonWrapper = UIView(frame: CGRect(x: 0, y: 0, width: 45.0, height: 45.0));

2. 或者您可以更改Button的yOffset值，

   let buttonWrapper = UIView(frame: CGRect(x: 0, y: -8, width: 60.0, height: 60.0));